Creative DNS

[Jeremy Lunn]

On Mon, Apr 17, 2000 at 11:34:56AM +1200, Parker Shaw wrote:
> Thanks for your explanation because I have the similar question.
> 
> But, my further question is:
> 
> Since you have multiple names "IN A" into the same IP address,
> how to do reverse lookup for that IP?

Reverse lookup is very different.  It would be impossiable (well slow)
to go through every nameserver on the internet and ask if an IP was in
it's zone.  So instead you look it up different.  Say the IP address is
202.169.14.4, it would be re-written to look like
4.14.169.202.in-addr.arpa.  So your nameserver would first query the
root nameservers and get the IP to contact a nameserver that is
authoritive for arpa, then it would query that nameserver to get the
nameserver for in-addr and then it would query it to get the nameserver
for 202, then 169, then 14 then finally get hostname for 4.
> 
> Thanks, a lot. (^_^)
> 
> BTW, any good online doc for DNS?

I never found any good online books, but DNS & Bind (ISBN:
1-56592-512-2) published by O'Reilly is a very good book.  Can be found
at: http://www.oreilly.com/catalog/dns3/.

-- 
Jeremy Lunn
Melbourne, Australia
ICQ: 19255837